Some current conventional vehicle wheel alignment systems use a computer-aided, three-dimensional (3D) machine vision alignment system. In such a system, one or more cameras view targets attached to the wheels of the vehicle. A computer in the alignment system analyzes the images of the targets to determine wheel position and alignment of the vehicle wheels from the wheel position data. The computer typically guides an operator to properly adjust the wheels for precise alignment, based on calculations obtained from processing of the image data. A wheel alignment system or aligner of this image processing type is sometimes called a “3D aligner.” An example of a vehicle wheel aligner using such image processing is the Visualiner 3D or “V3D”, commercially available from Snap-on Equipment of Conway, Ark., a division of Snap-on Incorporated.
In automotive service facilities, it is often necessary to raise the vehicle off the floor to a convenient height, so the technician has easy access to the underside of the vehicle (for example, to perform a wheel alignment). An automotive lift is commonly used for this purpose, having parallel tracks or runways which are hydraulically operated to raise the vehicle. The above-described machine vision wheel alignment systems typically include such a lift or “alignment rack” for positioning the vehicle relative to the cameras, and for allowing the technician to easily adjust the vehicle suspension components.
The technician must drive the vehicle onto the lift and position it correctly prior to beginning any work on the vehicle. At the lowest height, called the “drive-on height,” the lift top surface is often 12 to 18 inches above floor level, so there is a danger to the vehicle and the technician if the vehicle is not sufficiently centered on the runways as it is driven on to the lift. Common solutions to this problem have been the use of a convex mirror to allow a view of the front of the vehicle, or a second technician standing in front of the vehicle as it is driven on the lift, to direct the driver. Disadvantageously, such methods are inefficient, inconvenient, and/or imprecise, because the driver guides the vehicle using a limited amount of information.
There exists a need for an apparatus/method to safely and quickly allow a technician to drive a vehicle onto a lift.